Fix MIPS seccomp definitions for PRIMARY and SECONDARY arch

Set correct values for PRIMARY and SECONDARY arch definitions
to match LE MIPS architectures.
This change is resolving boot problem for mips32 arch with 3.18 kernel.
This also fixes mips64 issue related to PRIMARY_ARCH definition,
but in order to boot to home screen it needs additional syscalls whitelisted
which will be introduced in separate patch.

Tested on emulator:
emulator -kernel prebuilts/qemu-kernel/mips/3.18/kernel-qemu2

Change-Id: I68dfd136c22141933a8a8c5336db01a02f00b0df